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[WIP] Add VP8 encoder stage by porting C code from libvpx#14

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copilot/implement-vp8-encoder-stage
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[WIP] Add VP8 encoder stage by porting C code from libvpx#14
Copilot wants to merge 6 commits intomasterfrom
copilot/implement-vp8-encoder-stage

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Copilot AI commented Feb 17, 2026

VP8 Encoder Completion Plan

Already Completed ✅

  • Core encoder data structures (VP8_COMP, MACROBLOCK, etc.)
  • Encoding utilities (treewriter, tokenize, modecosts)
  • Transform (dct.cs - fully functional)
  • Skeleton implementations (encodeframe, encodemb, encodeintra, bitstream, mcomp, rdopt, encodemv, vp8_quantize)

Phase 1: Missing Critical Files

  • Port ratectrl.cs (rate control)
  • Port picklpf.cs (loop filter selection)
  • Port onyxe_if.cs (main encoder interface)

Phase 2: Complete Core Skeleton Functions

  • Complete vp8_quantize.cs functions (quantize_b, quantize_mb, etc.)
  • Complete encodemb.cs functions (subtract, transform, optimize)
  • Complete encodeintra.cs functions (intra prediction encoding)
  • Complete bitstream.cs functions (pack_tokens, write headers)

Phase 3: Support Functions & Arrays

  • Add missing encoding arrays to entropymode.cs
  • Add token structures and arrays
  • Add DSP functions (subtract_block, etc.)
  • Complete boolhuff.cs encoder functions if needed

Phase 4: Main Encoder Integration

  • Complete onyxe_if.cs initialization (vp8_create_compressor)
  • Complete onyxe_if.cs encoding (vp8_get_compressed_data)
  • Integrate into VP8Codec.cs EncodeVideo method

Phase 5: Testing & Validation

  • Build and test compilation
  • Create basic encoder test
  • Test with simple frame encoding
  • Debug and fix issues

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Copilot AI and others added 5 commits February 17, 2026 08:57
- Created src/onyxe_int.cs with VP8_COMP, VP8_CONFIG, CODING_CONTEXT,
  LAYER_CONTEXT, TWOPASS_RC, and related encoder structures
- Created src/block.cs with MACROBLOCK, BLOCK, and PARTITION_INFO structures
- Updated src/vpx_encoder.cs with vp8e_tuning enum and constants
- Follows decoder porting patterns with proper type conversions
- All structures are data-only (no implementation yet)
- Renamed static class to vp8_block to avoid naming conflicts

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This commit ports three essential encoder utility files from libvpx to C#:

1. treewriter.cs (7.1 KB)
   - Encoder equivalent of treereader.cs
   - Provides tree-based bitstream writing
   - Cost calculation functions for rate-distortion optimization
   - Source: libvpx/vp8/encoder/treewriter.{c,h}

2. tokenize.cs (131 KB)
   - DCT coefficient tokenization with complete lookup tables
   - dct_value_cost[4096]: Bit costs for all DCT values [-2048 to +2047]
   - dct_value_tokens[4096]: Token/Extra pairs for all values
   - Safe accessor methods: GetDctValueCost() and GetDctValueToken()
   - Sources: libvpx/vp8/encoder/tokenize.{c,h}, dct_value_{cost,tokens}.h

3. modecosts.cs (4.4 KB)
   - Calculates bit costs for prediction modes
   - Used in rate-distortion optimization during encoding
   - Source: libvpx/vp8/encoder/modecosts.{c,h}

Implementation features:
- All files compile successfully (dotnet build)
- Follow established patterns from decoder files
- Include proper copyright headers with correct dates
- Use unsafe code appropriately for pointer operations
- Provide both safe and unsafe API variants
- Include comprehensive XML documentation
- Pass security analysis (CodeQL)
- Pass validation tests

These utilities provide the foundation for porting the main encoding loop
and related functions (bitstream writing, frame encoding, quantization).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Added dct.cs: Forward DCT and WHT (Walsh-Hadamard Transform) for 4x4 blocks
- Added vp8_quantize.cs: Forward quantization functions (skeleton implementation)
- Added encodemv.cs: Motion vector encoding to bitstream (skeleton implementation)
- Enhanced entropy.cs: Added vp8_default_zig_zag1d array for coefficient ordering
- Enhanced entropymode.cs: Added vp8_small_mvencodings token array for MV coding
- Enhanced treewriter.cs: Added vp8_tree_probs_from_distribution helper function
- Enhanced systemdependent.cs: Added vpx_clear_system_state() stub function

Note: vp8_quantize.cs and encodemv.cs are skeleton implementations as they
require complete VP8_COMP and MACROBLOCK encoder structures that are not
fully ported yet. The DCT transform implementation is complete and functional.

These files provide the foundation for the VP8 encoding pipeline and will
be fully implemented once the main encoder structures are ported.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Added encodemb.cs: Macroblock encoding functions (transform, quantize, optimize)
- Added encodeintra.cs: Intra prediction encoding for key frames
- Added bitstream.cs: Bitstream generation and packing functions

These files provide skeleton implementations with TODO markers for:
- Function pointer handling in MACROBLOCK (short_fdct8x4, short_walsh4x4, quantize_b)
- Token encoding structures (vp8_token, vp8_extra_bit_struct)
- Tree encoding arrays (mode encodings for Y, UV, B, split modes)
- RD optimization algorithms
- Coefficient probability updates
- Full bitstream packing logic

The implementations compile successfully and provide the necessary entry
points for the VP8 encoding pipeline. Many functions are marked as TODO
and require additional encoder context (VP8_COMP, TOKENEXTRA structures)
to be fully functional.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Add skeleton C# implementations for three core encoder files:

1. encodeframe.cs - Main frame encoding pipeline
   - Activity masking for adaptive quantization
   - Macroblock setup and encoding
   - Main vp8_encode_frame entry point
   - Clear structure with TODO markers for implementation

2. mcomp.cs - Motion compensation and search
   - Motion vector bit costing
   - Search site initialization (diamond, 8-point)
   - Sub-pixel refinement (1/2-pel, 1/4-pel)
   - Integer-pel search (hex, diamond, full search)
   - Multiple optimization variants (C, SIMD)

3. rdopt.cs - Rate-distortion optimization
   - RD cost calculation and constants
   - Mode decision for intra (DC, V, H, TM, B_PRED)
   - Mode decision for inter (ZERO, NEAREST, NEAR, NEW, SPLIT)
   - Motion vector prediction
   - Helper utilities (sorting, plane pointers)

These are skeleton implementations following decoder patterns:
- Proper copyright headers
- Static unsafe classes
- Main function signatures defined
- Comprehensive TODO comments explaining logic
- Clear documentation of algorithm flow
- Can be incrementally completed

Files compile successfully with no errors.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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